ISSN:
0449-2978
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Several samples of a copolymer were examined by means of equilibrium centrifugation in a density gradient. The results for the samples without compositional distribution (homogeneous polymers) were used to determine the relation between the chemical composition and the distance from the center of rotation. For one of the homogeneous polymers a quantitative analysis of the schlieren curve was made in order to show the kind of accuracy that can be achieved. For the inhomogeneous polymer it was found that the schlieren curve could, in principle, be described quantitatively by the assumption that fluctuations in composition are independent of fluctuations in molecular weight, but on this basis the average square of the fluctuations in composition is more than four times smaller than the value derived from chromatographic data. A more satisfactory explanation of the experimental results is provided by assuming a linear correlation between average molecular weight and composition, but it is not claimed that this is necessarily the only model that explains the data.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1971.160091009
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